this is my account ; when i see open tournaments tab , i see 5 tounaments
{ having different name }
and one day my friend opened his own account from my computer , he was just being able to see 3 tournaments.... Why so ?

i wanna know all the possible reasons , thanks in advance

There may be open seat prerequisites that you fulfill and he does not.

Tournament creators can define prerequisites that players must meet in order to join their tournaments. There must have been two tournaments that you qualified for that your friend did not. See http://wiki.warlight.net/index.php/Open_Seat_Prerequisites. You can click on the tournament, then Settings, then Open Seat Prerequisites to see what they are.